The article elaborates and exemplifies a potential categorization of the reasons for using philosophy, in particular the philosophy of mathematics, in mathematics education and approaches to doing so-the so-called "whys" and "hows". More precisely, the "whys" are divided into the two categories of "philosophy as a tool" for teaching and learning mathematics, and "philosophy as a goal", referring to a stance of considering it a purpose in itself to teach students certain aspects regarding the philosophy of mathematics. A division of the "hows" into three different categories is offered: illumination approaches; modules approaches; and philosophy-based approaches. A major part of the article is spent on providing illustrative exemplifications of each of these approaches by referring to already implemented uses of philosophy of mathematics in mathematics education as well as by suggesting new ones.